In Mrs. Charles Frederick (Martha Rigden, died 1794), George Romney captures the elegance of Martha Rigden. The painting features rich colors, predominantly warm tones that enhance her graceful figure.

Rigden is depicted in a fashionable gown, adorned with intricate details that reflect the style of the late 18th century. The background is softly rendered, allowing the focus to remain on her poised expression and attire. Romney's technique is evident in the smooth application of oil paint, creating a lifelike representation of Rigden's features. The brushwork is delicate, particularly in the rendering of her skin and fabric textures.

The composition is balanced, with Rigden positioned centrally, drawing the viewer's eye directly to her. The painting measures approximately 76 x 63 cm, making it a substantial work for a portrait. George Romney was a prominent portrait painter in the 18th century, known for his ability to convey personality and character. This particular work showcases his skill in capturing the essence of his sitters.

Interestingly, Martha Rigden was the wife of Charles Frederick, a notable figure of the time, which adds historical significance to the portrait. Romney's portraits often reflect the social status and fashion of his subjects, making them valuable records of the period.